Process for making photomechanical color-printing plates.



V F; T. POWERS. PROCESS FOR MAKING PHOTOMECHANICAL COLOR PRINTING PLATES.

' APPLICATION FILED IULY 6.1916. 1 ,27 2,52 1 Patented July 16, 1918.

1 I I r:

' A ITORNEYS FRANK T. POWERS, OF NEW YORK, N. Y., ASSIGNOR TO 2OWERS PHOTO ENG-BAKING COIEPAN'Y, OF NEW YORK, N. Y. A CORPORATION OF NEW YORK.

PROCESS FOR MAKING PHOTOMECHANICAL COLOR-PRINTING PLATES.

Specification of Letters Patent.

Patented July 16, 1918.

Application filed July 6, 1916. Serial No. 107,843.

To all whom it may concern:

Be it known that I, FRANK T. Pownns, a citizen of the United States, and a resident of New York, in the county and State of New York, have invented certain new and useful Improvements in Processes for Mak-.

to processes for making color plates having a grain figure surface, although the invention is applicable to the production of some other'kinds of plates as well.

Objects and advantages of the invention will be set forth in part hereinafter, and in part will be. obvious herefrom, such objects and advantages being realizedthrou h the steps, processes and instrumentalitles set forth in the appended claims.

The invention consists in the novel steps, succession of steps, processes and improvements herein shown and described.

The accompanyin drawings, referred to herein and constituting a part hereof, illustrate one manner of carrying out my invention, the drawings being diagrammatic in character.v

Of the drawings:

Figure 1 represents the making of a line ne ative from the original copy;

ig. 2 represents the making of a line plate from the line negative;

Fig.- 3 represents a print made from the line plate and a color blocked in on a portion thereof plate from the negative made in'Fig. 4.

In carrying out my process in the preferred manner, it is applied to the production of photo-mechanical plates for threecolor or other multi-color work, and the process will be described. as applied to the inaking of the red, blue and yellow plates from a plain line drawing or'equivalent copy. It will be considered that the copy is a line drawing, which is set up on the copy board 1 of the camera 2, and aplain line negative 3 is made therefrom, that 1s, a negative without any screen figure. From this line negative, a line plate 4 is'made in any usual or acceptable manner, which will usually consist in applying to the surface of the plate a light sensitive layer, such as albumin containing silver or chromic salts, and properly developing and etching the plate after exposure. The making of the line plate need not be described in further detail.

From the line plate there is taken upon paper, or other suitable medium 5, an impression 6, which impression will show the copy or subject in outline. This impression is taken preferably in a blue color, or other color which is eliminable in usual photo graphic processes.

On this impression taken from the line plate, the colors desired in the final impression or blocked in or applied as shown at 7 in Fig. 3, and this may be done by hand, or with the air brush, or otherwise, as may be desirable or convenient. So far as concerns many features of the invention, a number of impressions may be taken from the line plate referred to, and the several colors, such as the primary colors, may be blocked in or applied, the one color on one of said impressions from the line plate, and another color on another of said impressions, and' the third color on a third of such impressions, if desired. In one aspect of the invention, the secondary or other actual colors may be blocked in or applied on the impres sion taken from the line plate, and suitable light filters be used to separate the primary colors in successively photographing such an impression for the several final printing plates, by the superimposed printing of which plates the colored picture is produced.

After the colors are ap lied or blocked in on the impression taken rom the line plate, in any of the ways mentioned, or othewise, the three color plates are made therefrom. It may be considered that the three primary colors have been blocked in on three imressions or-prints taken from the line plate.

11 such case, a print or impression so colored is set up on the copy board of the camera as indicated at 8 in Fig. 4, or otherwise positioned, and a negative thereof made in the camera by exposure of a' sensitized plate through a half-tone screen, say, for use in making the red printing plate. If the ordinary half-tone screen is used, thereis used but will cut out the cross or perpendicular rulings. Thus thescreen figures produced in the negative will consist of one way parallel rulings, although so far as concerns certain .features of the invention, this may be varied. Itwill be understood also, that where the impression photographed, that is, constituting the copy 1n this instance, is in secondary colors, a proper color filter will beused- H From the negative 9 so made,'a plate 10 is produced in the usual manner for halftone plates, whichis briefly to sensitize the surface of a metal plate, such as copper, expose it to light under the half-tone, or screen figure negative, and then develop and'etch it. Similarly, a printing plate may be made for the blue color from a suitable copy produced from an impression or print takenfrom the line plate. With this second plate, however, the slitstop will be given a quar- .ter turn, or changed in position by a quadrant, and thereby in the camera, the halftone screen will produce on the sensitized plate which is to constitute the negative, the one way screen figures, that is, the parallel lines or rulings all running one way and per pendicular, that is, at right angles to the screen figure lines on the first negative, or red printing plate negative, already described. I

In making the yellow printing plate, the procedure will be generally the same as with the red and blue plates, but the usual stop may be employed in the camera and the v full screen figure, or the cross lines or rulings of the half-tone screen will appear on the negative, in the form of the usual half-tone dots, varying according to the lights and shadows in the usual manner,

From these different negatives, plates are made in the usual manner, that is, in the case of each negative, exposin therebeneath a sensitized metal late, which plate is then developed and etc ed. These plates are then the various desiredprimary colors in such portions and disposltion as may be desired,

printed in superimposition in inks of the proper colors, in a well-understood manner.

What I claim as my invention and desire to secure by Letters Patent is:-

1. The process of making. color printing plates, which comprises making a line negative from the colored copy, making a l1ne' plate from said line negative, taking a plurality of impressions from said line'plate, applying to these impressions, respectively,

making screen figure negatives of the various colored impressions by making the red negative with the screen rulings running one way only, making the blue negative with the screen rulings running one 'way' only and,

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substantially at right angles to the rulings in the red negative, making the yellow negative with the rulings running both ways, and making the corresponding printing plates from said negatives. V

2'. The process of making color printing plates which comprises making alinenegative from the coloi'edcopy,'1'naking a line plate from said line negative, takingan impressionfrom said line plate, coloring said impression as desired, maklngthree colorplates therefrom, for red, blue and yellow;

making the red plate with screen rulings running one way only, vmaking the blue running one way only, making the blue plate with screen rulings running one way only, and at right angles to those of the red plate, and making the yellow vplate with the cross rulings.

4:. The process of making color printing plates which comprises making a line negative from the colored copy, makings line plate fronrsaid line negative, taking an impressionfrom said line plate, coloring said impression as desired by hand, making three color plates therefrom, for red, blue and yellow, making the red plate with screen rulin'gs running one way only,making the blue plate with screen rulings running one way only, and at right angles to those of the red plate, and making the yellow plate;

' 5. The process of making color printing plates which comprises making a line negative from a colored copy, making a line plate from said line negative, taking an impression from said line plate, appiyingthere- ,to one or. more colors in such portions and dispositions as may be desired, making a one color screen figure negative from said colored impression with the screen rulings running one way only, making a screen figure negative for another color with the screen figures running in a substantially perpendicular direction, and making the re-m spective color plates from said negatives. 'In testimony whereof, I have signed my name to this specificatiomin the presence of .two subscribing. witnesses.

FRANK T, POWERS,

Witnesses:

JOHN D. MORGAN, LoursA' Lorna. 

